The concept of providing a one piece sharpening device with a continuous abrasive surface is known. U.S. Pat. No. 5,520,374 to Wilson discloses a generally rectangular and elongated wedge-shaped ceramic stone. Likewise, the prior art, including Wilson, discloses the use of a semi-circular groove, as shown in cross-section, extending lengthwise across the face of a device. Other examples of groove features, as found in the prior art, include U.S. Pat. Nos. 6,074,293, 6,361,408 and 6,949,018 to Bleir.
Other references in the prior art are directed to providing a broad, flat sharpening surface positioned at particular angle from the work surface. U.S. Pat. No. 6,146,257 to Himeno, et al, attempts to address this requirement by providing a complex combination of a base plate, guide member, and manually operated positioning device, to hold a flat sharpening surface at a designated angle, on a fixed, flat work surface. U.S. Pat. No. 6,971,949 attempts to address this by providing a separate sharpening “guide” to be placed upon an abrasive surface and the dental instrument moved in cooperation with the various angle options provided.
Various dental instruments require different parameters relative to an abrasive surface for sharpening them. Common errors in sharpening include the creation of an improper bevel as well as sharpening the toe of a curette, which is intended to remain rounded, to a point.
Other dental instruments have concave surfaces which are difficult to sharpen on a flat surface and in best practice require a rounded edge on the abrasive sharpening surface.
While dental instruments may be routinely sharpened, there are occasions when they must be sharpened at chair-side and with minimal disruption of an ongoing procedure.
A common technique, long taught in dental schools, for using a hand-held sharpener for sharpening, requires holding the instrument to be sharpened in one hand, with its face parallel to the work surface, and the sharpening stone in the other hand. The sharpening stone is positioned against the instrument so that the sharpening face is angled at approximately 15° from the generally horizontal work surface. The practitioner must maintain this angle during the sharpening process, to properly sharpen the instrument.
With current hand-held sharpeners, finding and maintaining the correct, optimal angle is often a matter of educated guesswork, unless a line or other reference guide is provided or imposed upon the edge of the work surface. As stated, prior art attempts to address this issue have required significant additional device elements, and have required unwarranted and time consuming complexity as compared to the use of a hand-held, one piece sharpener. The prior art as well, has in general failed to combine the sharpening requirements for various dental instruments, as referenced above, in a simple, one-piece hand-held sharpener.
The present invention addresses the short-comings of the prior art by providing a concise, one-piece, sharpening device designed to be used for routine maintenance, as well as chair-side during procedures, as necessary, and which allows a practitioner to accurately and easily gauge and maintain the correct sharpening angle, together with multiple-sized sharpening grooves, as well as rounded edges for concave instrument surfaces.